Pharmacologic doses of estrogen and progesterone alter the time course of ovum transport through the rabbit oviduct by mechanisms as yet undefined. The proposed experiments will utilize in vivo perfusion to allow differential treatment of the whole animal and/or one oviduct with steroids, antiestrogens and inhibitors of protein synthesis. The goals are to ascertain: 1) whether the altered ovum transport rate is mediated by a direct effect of the steroids on the oviduct, 2) the molecular mechanism(s) by which the steroids alter ovum transport rates.